Catalytic treatment of crude oils



Jan. 28, 1964 H. G. CORNEIL ET AL CATALYTIC TREATMENT OF CRUDE OILSFiled Oct. 19, 1959 COMPRESSOR 52 48 OFF-GAS REACTOR --REAOTOR l6,-SEPARATOR cglllni "3 24 32 as 42 4-5 |3 MPRE HEATER coouza nvonoseu 62X 22 DISTILLATION 36 34 zone K"BO INVENTORS.

HAMPTON G. CORNEIL, RICHARD S. MANNE, GEORGE R. L. SHEPHERD, ARMAND M.SOUBY ATTORNEY.

United States Patent Ofifice 3,119,765 Patented Jan. 28, 1964 3,119,765CATALYTIC TREATMENT OF CRUDE OILS Hampton G. Corneil, Richard S. Manne,George R. L.

Shepherd, and Armand M. Souby, Baytown, Tex., as-

signors, by mesne assignments, to Essa Research and Engineering Company,Elizabeth, N.J., a corporation of Delaware Filed Oct. 19, 1959, Ser. No.847,298 3 Claims. (Cl. 208-210) This invention relates to a method forthe catalytic treatment of petroleum hydrocarbon crude oils.

More particularly, this invention relates to a catalytic hydrotreatingprocess for the upgrading of hydrocarbon crude oils.

Petroleum hydrocarbon crude oils are comprised of a wide variety ofcomponents boiling over a wide range. Accordingly, it is the customarypractice to fractionate the crude oil and to separately treat thevarious fractions that are obtained.

In accordance with the present invention, however, a method is providedwherein the crude oil is treated in a manner to convert selectively thehigher boiling fractions thereof and in order to provide for asubstantially desulfurized product.

Briefly, in accordance with the present invention, a petroleumhydrocarbon crude oil is passed upwardly through a fixed bed of asupported cobalt molybdate cata lyst in the presence of controlledamounts of added hydrogen in order to desulfurize partially the crudeoil and in order to at least partially convert the heavier components ofthe crude oil. The total effluent is separated into a vapor phasefraction which is further treated with hydrogen in the presence of asupported cobalt molybdate catalyst in order to provide a substantiallydesulfurized product and a liquid phase which is preferably recycled.

The feed stocks for the present invention are petroleum hydrocarboncrude oils which contain residuum components such as total crudes,topped crudes, residua, etc. and which are further characterized bycontaining about 50 to 100 volume percent of components boiling aboveabout 800 F.

The catalyst that is utilized in acordance with the present invention isa supported cobalt molybdate catalyst such as a catalyst comprising fromabout 5 to 20 weight percent of cobalt molybdate supported on a highsurface area carrier such as synthetic gamma alumina, bauxite, etc.

The conversion conditions to be utilized in both the first and secondstage include a pressure within the range of about 200 to 1000 p.s.i.g.,a temperature within the range of about 700 to 800 F., a space velocitywithin the range of about 0.5 to 5 v./v./hr., and a hydrogen charge ratewithin the range of 700 to 7000 standard cubic feet of hydrogen perbarrel of feed. The first stage reaction is conducted upflow, the secondstage reaction being conducted either upflow or downflow, as desired.

The reaction conditions may be the same or different in the second stageas compared with the first stage within the above-described limits.Thus, the second stage may be operated at the same pressure or a lowerpressure if not less than about 200 p.s.i.g.

Numerous advantages are obtained in accordance with the presentinvention. Thus, at least a portion of the residuum components of thecrude oil (those boiling above about 1000 F.) are converted to lowerboiling desulfurized products. When appropriate recycle operations areemployed, substantially all of the residuum components may be thusconverted. In addition a high yield of substantially sulfur-free heavyand light gas oil fractions are obtainable, together with a good yieldof low sulfur naphtha fractions containing reduced quantities ofolefins.

The invention will be further illustrated with reference to theaccompanying drawing wherein the single figure is a schematic flow sheetillustrating a preferred form of the present invention.

Turning now to the drawing, there is shown a first stage reactor 10 anda second stage reactor 12. A bed of particulate supported cobaltmolybdate such as gamma alumina supported cobalt molybdate is providedin each of the reactors 10 and 12.

A crude oil from any suitable source (not shown) may be charged by wayof a line 14 to a preheater 16 wherein the charge is heated to reactiontemperature. Make-up hydrogen from an extraneous source may be added tothe crude in the line 14 by way of a line 18, recycle off-gas rich inhydrogen may be charged to the crude line 14 by way of a recycle line20, and heavy conversion components may be charged to the line 14 by wayof a liquids recycle line 22.

The thus-prepared mixture of feed components is heated in the preheater16 to a desired conversion temperature and discharged from thence by wayof a charge line 24 leading to the bottom of the first stage reactionzone 10. The feed mixture is passed upflow through the first stagereactor 10 under conversion conditions as above set forth. As aconsequence, the liquid components of the feed stock are partiallydesulfurized and, in addition, partial conversion of heavier componentsof the feed stock occurs. The total efiiuent from the reaction zone 10is discharged from the top thereof by way of a discharge line 26 leadingto a separator 28 wherein the total efliucnt is separated into a gasphase and a liquid phase. The gas phase, which will contain asubstantial portion of the charge components, is charged to the secondstage reactor 12 by way of a line 30 for further treatment under theabove-described conversion conditions. As a consequence of the secondstage, the sulfur content of the vapor phase fraction 30 is materiallyreduced and, in addition, olefins that may be present in the conversionproducts are at least partially saturated with hydrogen.

The liquid fraction from the separator 28 is discharged by way of abottoms draw-off line 32 controlled by a valve 34. All or a selectedportion of the bottoms fraction may be discharged from the system forfurther treatment. However, in accordance with a preferred embodiment ofthe present invention, the liquid fraction is recycled by closing thevalve 34 and by opening the valve 36 in the above-mentioned recycle line22.

The total efiluent from the second stage reactor 12 is discharged by aline 38 leading to a cooler 4-0 wherein liquefiable hydrocarbons arecondensed. From cooler 40, the total efiiuent is charged by a line 42 toa second separator 44. A gas phase consisting principally of hydrogenand containing normally gaseous hydrocarbons is taken overhead by way ofa line 4-6. Normally, at least a portion of the off-gas will bedischarged from the systern by a discharge line 48 controlled by a valve50. All or a selected portion of the off-gas may be charged by way of aline 52 controlled by a valve 54 to a compressor 56 discharging into theabove-described recycle line 20.

The liquid phase from the second separator 44 is discharged by way of aline 58 leading to further treating facilities. Thus, for example, theliquid fraction may be charged by way of a line 58 to a distillationcolumn 60 wherein the liquid fraction may be separated into a naphthafraction 62, a kerosene fraction 64, a light gas oil fraction 66, aheavy gas oil fraction 68, and a residuum fraction 70.

The residuum fraction may be discharged from the system by opening thevalve 72 in the bottoms discharge line 70. Alternately, it may bereturned by way of a branch line 74 controlled by a valve 76 to therecycle line 22.

Similarly, all of the heavy gas oil may be discharged from the systemfor further treatment (e.g., catalytic cracking) by opening the valve 78in the discharge line 63. Alternately, a valve 80 in a recycle line 82leading to the recycle line 74 may be opened whereby at least a portionof the heavy gas oil may be returned to the recycle line 22.

The invention will be further illustrated by the following specificexamples which are given by way of illustration and not intended aslimitations on the scope of this invention.

EXAMPLE I In order to illustrate the necessity for operating the firststage in an upfiow phase, a crude oil is processed under superficiallyidentical reaction conditions in two separate reactors, one reactorbeing operated on a downflow basis and the other being operated on anupfiow basis.

The composition of the feed stock is set forth in Table I, the reactionconditions employed and the results obtainable are set forth in TableII.

Table] INSPECTIONS ON CRUDE OIL CHARGED Gravity, API 25.9 Sulfur, wt.percent 2.70 Viscosity at 80 F., SSU 270 Viscosity at 100 F., SSU 195Ash, p.p.m 94 ASTM distillation: 1

IBP, F 181 5% off at, "F 257 oil at, F 301 20% off at, F 398 30% off at,F 544 40% off at, 'F 647 60% off at, F 790 70% off at, "F 923 DuplicateASTM D-S gas oil distillations to 600 F., followed by ASTM D-1160 10 mm.distillation on combined bottoms. Temperatures at 10 mm. converted tothe equivalent temperatures at atmospheric pressure shown above by meansof the chart on page 42 of Maxwell, Data Book on Hydrocarbons, VonNostrund (New York, 1950).

Table II FIRST'STAGE HYDRQDESULFURIZATION [800 p.s.i.g., 745 F. inlet,0.9 v./v./hour, 1700 s.c.f. Ila/B] Type of Operation Crude DownflowUpflow Charged Overall Desullurization, Percent 67 63 Vol. Wt. V01. Wt.Distillation Fractions Per- Per- Per Percent 1 cent cent 1 cent C 375 F.Naphtha 18.1 0.03 17. 8 0.02 375-530 F. Kerosene 12.1 0.22 14.3 0. 04530600 F. Light Gas Oil 5. 6 0. 75 7. 3 0.07 600-1,040 F. Gas Oil 33. 52.3 38.1 0.31 1,040 F.+Residuurn 30. 2 3. 8 22. 1 2. 9

Total 0 and Heavier 99. 5 2. 7 99. 6 0. 89

1 Based on original crude charged.

From Table II, it will be observed that there is a significantconversion of the 1040 F.+ residuum fraction in the upfiow reactor andthat a much lesser conversion is obtained with respect to the downflowreactor. It will be noted, moreover, that although enhanced yields ofkerosene and naphtha are obtained by the upfiow reaction conducted inaccordance with the present invention, substantially the same quantitiesof heavy and light gas oil are obtained in both instances.

As is seen by the analysis of sulfur, however, the first stage reactionis not satisfactory from the point of sulfur removal in thatsignificantly larger amounts of sulfur are present in the gas oilfractions from the upfiow reaction as compared with the sulfur removalobtained by the downflow reaction.

However, further treatment of the vapor phase from the first stagereaction here illustrated significantly reduces the sulfur content ofthe distillate materials.

EXAMPLE II In order to illustrate the effects obtainable by the twostage process of the present invention, a separate hydrocarbon feedstock is treated in stages.

The feed stock that is utilized is a West Texas vacuum ASTMdistillation, percent off at 1040 F 9.0

l\l'.ethod of ASTM D-1160. but run at 1 mm. pressure instead of 10mm.Temperature converted to the equivalent at atmospheric pressure by meansof the chart on page 42 of Maxwell, Data Book on Hydrocarbons, VonNostrand (New York, 1950).

Treat the above-identified feed stock in the presence of a commercialcatalyst consisting of about 15 weight percent of cobalt molybdatesupported on gamma alumina under upfiow conversion conditions includinga pressure of about 800 p.s.i.g., an average reactor temperature ofabout 785 F., a space velocity of about 0.55 v./v./hr. and a hydrogencharge rate from about 2950 cubic feet of hydrogen per barrel. As aresult of the first stage reaction, about 57 percent desulfurization isobtained and about 60 percent of the 1040 F.+ material is converted tolighter products.

Separately collect the vapor and liquid products from the first stage.The mol percent of each component or fraction in the total reactorproduct and the percentage of that component or fraction in the vaporphase at the reactor outlet are set forth in Table IV.

Table IV Percent Component vaporized Component Total Treat two portionsof the vapor phase in accordance with the present invention in separateruns. Conduct one second-stage run at a pressure of about 400 p.s.i.g.and an average reaction temperature of about 766 F. Conduct the othersecond-stage higher pressure of 575 p.s.i.g. and a high reactiontemperature of about 787 F.

The reaction conditions employed and the gross results obtained are setforth in Table V.

Table V HYDRODESULFURIZATION OF VAPOR PHASEFRACTION OF PRODUCT FROMHYDRODESULFURIZATION OF CRUDE RESIDUUM Run No., HDS 2002 2008 Pressurep.s.i.g 400 575 Avg. Catalyst Temp, 766 787 Feed Rate, v./v./hr. 2.0 1.9Hz Rate, s.c.f./b 2,970 2, 870 Hz Consumption, s.c.f./b. 305 290 PercentDesulfurization 89 96 Liquid Product Yield, Vol. Percent of Feed 99. 695. 7

Feed

Inspections on Liquid Product:

Gravity, API 29. 4 30.9 31.0 Sulfur, Wt. Percent. 0.66 0.05 0.02Distillation Data- IBP, F. 345 162 168 FBI, F 1,004 1,004 1,004 IBP-430raction, Vol. Percent... 20. 2 23.0 23. 4 430-650 F. Fraction, Vol.Percent.-. 37.1 42. 4 44.9 650-1,004 F. Fraction, Vol. Percent. 42. 734. 6 31. 7

ZATION OF VAPOR PHASE PRODUCT FROM HYDRODE- SULFURIZATION OF CRUDERESIDUUM Run No., HDS Feed 2002 2008 Naphtha Fraction HEP-430 F.):

Gravity, API 49. 3 47. 3 46. 8 Sulfur, Wt. Percent 0.07 0.01 0. 02 Res.Oct No (+1 cc. TEL) 68.3 64.0 66.6 Aromatics, Percent 23. 4 24. 6 26. 6Bromine No., MgJgm 9. 7 2. 1 1. 5

Heating Oil Fraction (430650 F.

Gravity, API 30.1 30. 4 29.9 Sulfur, Wt. Percent 0.36 0.05 0.01 AnilinePoint, F l- 124 129 Neut. Value, rug. KOH/gm. 0. 20 0.04 0.01 Aromatics,Percent 55. 6 55.0 56. 3 Phenol Content, Wt. Percent- 0. 10 0.01 0.01Thiophenol Content, Wt. Perc 0. 006 0. 002 0.001 Bromine No., rug/gm11.0 3.0 3.1

Table VI-Cont1nued Run No., HDS Feed 2002 2008 Gas Oil Fraction(6501,004 F.):

Gravity, API 19.1 21. 9 22. 3 Sulfur, \Vt. Percent-- 0. 83 0.07 0. 04Nitrogen, Wt. Percent 0. 28 0.22 O. 20 Bromine No., mgJgm 13.1 9. 9 11.2Conradson Carbon, Wt. Percent.- 10.2 0.73 0. 44 Refractive Index at 67C., 7113 1. 5166 1. 5062 1. 5080 ASTM D-ll60 Distillation F 754 734 737804 754 747 908 807 795 984 890 883 1, 047 968 Aromatic Rings, Wt.Percent 20. 9 19. 5 21.2

Having described our invention, what is claimed is:

1. A method which comprises the steps of passing a crude petroleumhydrocarbon feed stock containing at least about 50 volume percent ofcomponents boiling above about 800 F. in an upfiow direction through afirst reaction zone containing a fixed bed of a supported cobalt molybdate catalyst under conversion conditions including a temperature of700 to 800 F. and a pressure of 200 to 1000' p.s.i.g. at a spacevelocity of about 0.5 to 5 volumes of feed stock per volume of catalystper hour in the presence of 700 to 7000 cubic feet of hydrogen perbarrel of feed stock, separating the total efiluent from said firstreaction zone without substantial cooling thereof into a vaporizedfraction and a liquid fraction, recycling at least a portion of liquidfraction to said first reaction zone, passing said vaporized fractiondirectly after said sep a-ration through a second reaction zonecontaining a fixed bed of supported cobalt molybdate catalyst underconversion conditions similar to those in the first reaction zone andrecovering a desulfurized product from the effluent from said secondreaction zone.

2. A method as in claim 1 wherein the effiuent from the second reactionzone is fractionated to separate cornponents boiling above about 800 F.from the remaining components of said eflluent, wherein the normallyliquid components of said effluent boiling below 800 F. are recoveredand wherein the components of said efiluent boiling above 800 F. arerecycled to said first reaction zone.

3. A method as in claim 2 wherein a hydrogen containing normally gaseousoff-gas product is recovered from the efiluent from said second reactionzone and wherein at least a portion of said oil-gas is recycled to saidfirst reaction zone to provide at least a portion of the hydrogen.

References Cited in the file of this patent UNITED STATES PATENTS2,771,401 Shepherd Nov. 20, 1956 2,902,436 Mills Sept. 1, 1959 2,909,476Hemminger Oct. 20, 1959 2,914,462 Hemrninger Nov. 24, 1959 2,934,492Hemminger et al Apr. 26, 1960

1. A METHOD WHICH COMPRISES THE STEPS OF PASSING A CRUDE PETROLEUMHYDROCARBON FEED STOCK CONTAINING AT LEAST ABOUT 50 VOLUME PERCENT OFCOMPONENTS BOILING ABOVE ABOUT 800*F. IN AN UPFLOW DIRECTION THROUGH AFIRST REACTION ZONE CONTAINING A FIXED BED OF A SUPPORTED COBALTMOLYBDATE CATALYST UNDER CONVERSION CONDITIONS INCLUDING A TEMPERATUREOF 700* TO 800*F. AND A PRESSURE OF 200 TO 1000 P.S.I.G AT A SPACEVELOCITY OF ABOUT 0.5 TO 5 VOLUMES OF FEED STOCK PER VOLUME OF CATALYSTPER HOUR IN THE PRESENCE OF 700 TO 7000 CUBIC FEET OF HYDROGEN PERBARREL OF FEED STOCK, SEPARATING THE TOTAL EFFLUENT FROM SAID FIRSTREACTION ZONE WITHOUT SUBSTANTIAL COOLING THEREOF INTO A VAPORIZEDFRACTION AND A LIQUID FRACTION, RECYCLING AT LEAST A PORITON OF LIQUIDFRACTION TO SAID FIRST REACTION ZONE, PASSING SAID VAPORIZED FRACTIONDIRECTLY AFTER SAID SEPARATION THROUGH A SECOND REACTION ZONE CONTAININGA FIXED BED OF SUPPORTED COBALT MOLYBDATE CATALYST UNDER A CONVERSIONCONDITIONS SIMILAR TO THOSE IN THE FIRST REACTION ZONE AND RECOVERING ADESULFURIZED PRODUCT FROM THE EFFLUENT FROM SAID SECOND REACTION ZONE.